1. Field of the Invention
This invention relates to folding wing structures and more particularly to a self-erecting, folded wing structure suitable for use on missiles and guided munitions. The invention further relates to high aspect ratio folding wings.
2. BACKGROUND OF THE INVENTION
It has long been understood in the aerospace and munitions arts that wings, stabilizers, and other control surfaces greatly improve missile or projectile performance and maneuverability. These various control surfaces allow for course correction and stabilization which greatly improves accuracy as well as allowing the implementation of highly advanced guidance and target seeking systems.
In many applications, such as aircraft borne missiles, mounting hardware used to support a missile on an aircraft body or wing can account for the volume occupied by wings on the munitions. That is, spacers and support structures position missiles so that their fixed wings clear any adjacent surfaces, However, in many applications, especially in armored vehicle, ship borne, and hand held launching devices, the missile launching mechanisms require the wings to be stowed interior to the missile and erected after launch. This allows for highly compact, simplified launching systems which are better suited to the limited volume or weight available for these applications.
However, it is important that the wings or stabilizers not sacrifice an unduly large amount of volume inside the missile, and not impact on the aerodynamic characteristics of the missile, or create a breach in any hermetic or RF seal provided around interior missile components.
Many self-erecting wings or wing structures have been developed in an attempt to meet these requirements. Many of the wing structures comprise wings that pivot or fold out from a recessed cavity in the side of a missile fuselage or airframe. The wings themselves generally comprise a rib support structure over which an aluminum or similar metallic skin is secured. Therefore, these wings represent "solid" folding wing structures which require a fairly large storage volume at least the size of the fully erected wing.
However, it has also been discovered that the use of flexible cover material, such as a mylar, nylon or graphite reinforced fiber, can decrease weight and bulk while still providing a wing of reasonable strength. A wing utilizing a flexible cover or fabric construction is illustrated in U.S. Pat. No. 4,411,398 issued to Wedertz et al.
In Wedertz et al, a fabric material is stretched between the side of a missile fuselage and a point located some distance out from the fuselage to form an aerodynamic surface. This is accomplished utilizing a series of pivoting arms attached to the missile which form a leading edge spar projecting out from the side of the missile. Fabric is stretched from the fuselage to the outer end of the spar. While this represents decreased volume and weight requirements, there are still several operational drawbacks. This type of wing lacks any type of surface support for the flexible material in order to maintain aerodynamic characteristics of the wing and decrease the effects of turbulence. Also, long leading edge spars must be made from fairly large bulky material to accommodate all of the stress exerted on the wing during flight. In addition, the spar mechanism makes it very difficult to achieve some types of wing structures, most notably a swept design with the wing trailing edge parallel to the leading edge.
Therefore, what is needed is a new type of folding wing design which takes advantage of a lightweight, small volume, flexible cover technique, while achieving surface strength and contour control more typically found in solid wing structures. In addition, it would be useful to achieve a flexible folding wing design which allows improved control over sweep angle configuration and larger aerodynamic spans.